MT_CLEAR_TAG
und_ptr = (char *) MT_CLEAR_TAG((size_t) ptr - underflow_range);
und_ptr = (char *) MT_CLEAR_TAG((size_t) ptr);
und_ptr = (char *) MT_CLEAR_TAG((size_t) ptr);
over_ptr = (char *) MT_CLEAR_TAG((size_t) ptr + tagged_size);
over_ptr = (char *) MT_CLEAR_TAG((size_t) ptr);
over_ptr = (char *) MT_CLEAR_TAG((size_t) ptr + tagged_size);
ptr = (void *)MT_CLEAR_TAG((unsigned long)ptr);
#define MT_CLEAR_TAGS(x) (MT_CLEAR_ATAG(MT_CLEAR_TAG(x)))